Compare these 2 engines

[CSL_Wanabee]

Which one of these engines would ultimately make more power on stock internals, regardless of cost:

E46 M3 engine, 343bhp stock and 550bhp @ 7psi with a supercharger kit

E92 335i engine, 300bhp stock on paper (boosted 12psi twin turbos), 320bhp in real life, 380bhp with a xede chip tune (increases air:fuel ratio to 12.5:1 or something from 11:1 stock - due to bmw's new direct injection technology) The stock compression ratio on this engine is quite high, how much power would it make if the two twin turbos were swapped for a GT35 say; would it be more than the supercharged M3 engine above? Also, would 550bhp even be possible at this compression ratio on stock internals? (the Gt-35's limit)

Basically, am asking what would the better buy be.

[maxfield]

E46 M3 tried and tested

[Ant]

E46 M3 tried and tested

Also, quite a few have shat themselves with a lot of loud pedal abuse, trackdays mainly, cant believe the claimed figures either, the BHP gain is way high for 7 psi in my experience.

I vote for a lower tech, lower stressed engine, with more boost

[jkarran]

E46 M3 engine, 343bhp stock and 550bhp @ 7psi with a supercharger kit

Those numbers don't really stack up, a VERY crude and somewhat optimistic check:

343 + 343x(7/14.7) = 506

That's before taking acount of SC drive losses (maybe 30bhp) and density loss due to heating.

If the kits do make 550bhp @ 7psi there must be a lot more going on than just the supercharger

jk

[maxfield]

http://www.activeautowerke.com/supercha ... 3/main.php

Ant always heard good things about AA superchargers.

[Turbo-Brown]

That's only a 60% increase which, when you consider I managed 58% with the same boost it's not so unrealistic I don't think, especially considering the vastly greater ability to breath the S54 has over the M20.

Don't think I'd want the high CR of the M3 engine though. Can see why they'd use a supercharger if that's been left standard, to make sure there's nothing preventing hot gasses from escaping.

[jonb]

Which one of these engines would ultimately make more power on stock internals, regardless of cost:

E46 M3 engine, 343bhp stock and 550bhp @ 7psi with a supercharger kit

E92 335i engine, 300bhp stock on paper (boosted 12psi twin turbos), 320bhp in real life, 380bhp with a xede chip tune (increases air:fuel ratio to 12.5:1 or something from 11:1 stock - due to bmw's new direct injection technology) The stock compression ratio on this engine is quite high, how much power would it make if the two twin turbos were swapped for a GT35 say; would it be more than the supercharged M3 engine above? Also, would 550bhp even be possible at this compression ratio on stock internals? (the Gt-35's limit)

Basically, am asking what would the better buy be.

550bhp @ 7psi on the e46. No way my friend. Way off. Try nearer 420bhp i guess.

The 335i will not be abill to make big numbers with that compression, no way. Well not for long anyways.

[Turbo-Brown]

Think it's gonna be a while before the average joe can start tinkering with direct injection engines as the injectors aren't likely to be available in larger sizes I wouldn't have thought.

[jkarran]

Think it's gonna be a while before the average joe can start tinkering with direct injection engines as the injectors aren't likely to be available in larger sizes I wouldn't have thought.

Could you not run a second rail in the inlet tracts? I could be talking crap, I don't know diesels at all. Actually... I'm assuming we're talking diesel 535?

jk

[Turbo-Brown]

Could you not run a second rail in the inlet tracts? I could be talking crap, I don't know diesels at all. Actually... I'm assuming we're talking diesel 535?

Think he's talking about the new petrol twin turbo thing which can presumably get away with a high CR as a result of the direct injecton.

I reckon that with conventional injection being used in addition to the standard system you'd run into problems with det.

Be a pain to mod the fuel delivery system too as the old style injectors need about 45psi, whereas DI ones run at massive pressures to enable them to deliver enough fuel in a tiny amount of time and against high cylinder pressures.

[jkarran]

Ah, not quite sure why but I always assumed that twin turbo 535 was a diesel
jk

[snoops]

the 535 twin turbo is a diesel but CSL_Wanabee is talking about the new 335i 3.0 twin turbo